This application proposes to add a neuroimaging arm to an NIH funded 12-month diet and physical activity intervention. Obesity is currently at epidemic proportions in the United States, affecting over 1/3rd of American adults. Impaired cognitive and brain function - manifested as mood disorders, impulsivity, and an increased risk for neurological pathology - are often unrecognized consequences of obesity. These consequences are especially unsettling in view of the increased prevalence of obesity during childhood and adolescence, when the education, intellectual growth, and the preparation for future career seeking are at its peak. Hence, it is a public health imperative to rigorously investigate the effects of obesity on neurocognitive functions and to explore the potential for weight loss to restore cognitive and brain function. The parent study has three groups: diet only (DIET), diet + moderate physical activity (MOD-PA), diet + high physical activity (HIGH-PA) and will be collecting a myriad of outcome measures including aortic pulse wave velocity, inflammatory markers, glucose and insulin, abdominal adiposity and body composition using dual-energy X-ray absorptiometry, cardiorespiratory fitness using a graded exercise test, accelerometry measured physical activity, and energy intake. In addition to the subjects collected in the parent study we will collect a group of no-contact control (CON) participants for both reliability and comparison purposes. Therefore, by adding brain imaging to this intervention, our proposal reflects a cost effective and innovative approach to investigate links between physical activity, weight loss, brain integrity, metabolic outcomes, and cognitive processing and offers an opportunity to collect data on brain health with minimal additional costs. Testing these links could transform the way that brain-body associations are considered when assessing the risk for brain dysfunction or treating obesity related behavioral problems. Our main aims include: Aim 1. To examine whether a 12-month physical activity and weight loss intervention on overweight and obese adults increases cortical volume and improves microstructural white matter integrity, Aim 2: Examine how increased physical activity and weight loss can change the functional dynamics of the brain as assessed by both task-related neural responses, cerebral blood flow, and resting state brain connectivity, Aim 3. Link the changes in brain integrity, function, and connectivity with intervention-induced changes in physiological measures of metabolic and inflammatory molecular pathways. Our project represents the first attempt to associate weight loss in a long-term intervention to changes in brain networks. It is highly innovative, cost-effective, and will add significantly to the scientifc literature. By leveraging an existing NIH funded program and by focusing on neuroimaging outcomes with a skilled and productive team of experts in both weight loss interventions and cutting-edge neuroimaging techniques, we will be able to address unanswered questions that have important theoretical and translational implications for obesity and brain health.